Single and dual arch mouthguards are known in the art. A single arch mouthguard receives either the upper or lower teeth of the human mouth. With varying degrees of success such devices protect the teeth from impacts. A dual arch mouthguard, in contrast, has upper and lower tooth-receiving channels which are designed to protect both the upper and lower teeth.
Still other dental appliances protect not only the teeth but also the temporomandibular joint (TMJ) and surrounding tissues from injury due to impact of the lower jaw. An example of such a device is described in U.S. Pat. No. 5,636,379. As described therein, the device is similar to a dual arch mouthguard in that it has upper and lower arch-shaped, tooth-receiving channels. However, the device is configured such that the lower arch or mandibular component is offset forwardly with respect to the upper arch or maxillary component so that the mandible is disposed in a slightly protruding position when the device is worn in the mouth. Such protrusion increases bone separation at the TMJ and surrounding area and thereby reduces potentially damaging effects experienced at the TMJ and surrounding tissues resulting from impacts on the lower jaw or mandible that one might encounter when participating in contact sports such as football, boxing, martial arts and the like.
In addition to the foregoing features, the device disclosed in U.S. Pat. No. 5,636,379 is constructed from two distinct plastics: a full arch inner shock absorbing plastic core which is enveloped by an outer plastic body that forms the upper and lower tooth-receiving arches of the device. The inner shock absorbing plastic is a relatively soft yet resilient plastic for absorbing impact force transferred from the wearer's jaw. In the commercial embodiment of the device disclosed in U.S. Pat. No. 5,636,379 marketed by Brain Pad, Inc. of Conshohocken, Pa., the inner shock absorbing plastic is a semi-rigid thermoplastic having a Shore A hardness of between about 40-50, preferably about 45, a density of less than 1.0 g/cm3, preferably between about 0.8-0.9 g/cm3, and which will not melt in boiling water. A suitable plastic for this purpose is HP-9450 thermoplastic elastomer (“TPE”) marketed by DIOSHY Co., Ltd. of Taiping City, Taiwan. The outer plastic is a thermoplastic of relatively low melting point that may be boiled or otherwise heated to soften the plastic. Upon sufficient softening, the user inserts the device into his or her mouth and bites down whereupon the user's teeth form an impression in the outer plastic. Thereafter, the device is permitted to cool whereby the outer plastic hardens, the impression becomes permanent, and the wearer is left with a custom-fit protective dental appliance.
While generally effective for its intended purposes, the device disclosed in U.S. Pat. No. 5,636,379, as well as its commercial manifestation, does not dissipate impact force in optimum fashion. That is, the shock absorbing inner plastic member exhibits greater than desired elastic rebound which, if not physically harmful, may result in discomfort to the wearer of the device upon receipt of an impact to the mandible. Also, it is believed that the full arch core member transmits force or shock not only to the molars but also the less firmly rooted teeth which may result in more discomfort being experienced by the user upon impact.
Other dual arch dental appliances are described in U.S. Pat. Nos. 5,259,762 and 5,624,257. Commercial embodiments of those appliances are marketed by Shock Doctor, Inc. of Minneapolis, Minn. The Shock Doctor devices, which consist of a substantially rigid dual arch inner core encased within a “boil and bite” outer layer, also fail to provide optimum comfort when a wearer experiences an impact to the jaw. It is believed that discomfort arises from the considerable force transmission characteristic of the material selected as the inner core as well as the fact that the inner core forms the entire upper and lower tooth-receiving channels of the device. As a consequence, impact forces are experienced by essentially all of the wearer's teeth rather than merely the more firmly rooted molars.
Other documents describe single arch mouthguards with shock absorbing pads located generally in the molar regions of the arch. Examples include U.S. Pat. Nos. 4,765,324 5,339,832 and 6,082,363. Most notably, such devices provide no stabilization of the mandible and no frontal and lateral impact protection for the mandibular teeth.
An advantage exists, therefore, for a shock absorbing dental appliance that protects the maxillary and mandibular teeth from impacts in all directions.
A further advantage exists for a shock absorbing dental appliance that stabilizes the mandible and protects the TMJ and surrounding tissue including the base of the skull from impacts to the jaw.
A further advantage exists for a shock absorbing dental appliance that protects teeth, the TMJ and related body parts in highly comfortable fashion.